This proposal addresses the need to provide widespread, time-resolved measurement of the chemical composition of atmospheric particles that are below 2.5 5m in diameter. These fine particles have been associated with increased morbidity and mortality. They play an indirect role in public health through their influence on global climate and their influence on the formation, albedo and lifetime of clouds. Our approach uses a "smart" sampler that collects sequential, ready-to-analyze samples on a single collection wafer, onto which is written all of the relevant collection data such as location, time and air volume. The collection wafer is handled in the laboratory by an autosampler ion chromatograph system that extracts, injects and analyzes the samples without manual handling by the laboratory operator. Further, the laboratory system is programmed to read the flash memory on the wafer and to combine the analytical data with the collection information to produce a reduced data set, with analyte concentrations expressed in 5g/m3 of air. This project seeks to refine, validate and demonstrate this system through ongoing development and field testing in conjunction with on-going NIH-funded epidemiology studies and ambient air monitoring programs. It also seeks to extend analytical capabilities to include the faster, more sensitive lab-on-a-chip analysis methods. We aim to provide a cost-effective method for hourly- resolved monitoring of the chemical constituents of airborne particulate for both environmental monitoring and exposure assessment studies. PUBLIC HEALTH RELEVANCE: Small airborne particles are associated with increased morbidity and mortality, and affect global climate through their influence on the formation and lifetime of clouds. This proposal addresses the need to better understand the origins and concentrations of these particles by providing an affordable means for time-resolved assay of their chemical composition.